resistive index

resistive index

an indicator of resistance of an organ to perfusion. In ultrasonography, it can be calculated from the peak systolic velocity and the end diastolic velocity of blood flow.
References in periodicals archive ?
An ultrasonic measurement called the renal arterial resistive index (RI) can be calculated by determining the ratio of change in renal (kidney) blood flow velocity between systole (when the heart contracts) and diastole (when the heart relaxes) to the systolic velocity.
The resistive index of renal arteries is the most widely used parameter to estimate the arteriolar vascular resistance and to evaluate renal haemodynamics.
Doppler sonography in renal artery stenosis-does the Resistive Index predict the success of intervention?
Flow pattern and vascular resistive index as predictor of malignancy risk in thyroid follicular neoplasms.
The resistive index is calculated from blood flow velocities in vessels during the cardiac cycle, measured by pulsed-wave Doppler ultrasound [10].
Incomplete torsion initially results in venous compromise which can be seen on Doppler ultrasound as an elevated resistive index and elevated velocity at the main renal artery anastomosis [4].
Spectral waveforms were taken from the intranodal vessel to document the Doppler indices: resistive index (RI) and pulsatility index (PI).
Biparital diameter in mm femoral length in mm abdominal circumference in mm expected fetal birth weight in grams percentile weight amniotic fluid index in cm both uterine arteries resistive index umbilical artery systolic / diastolic ratio and analysis of waveform patterns of arteries.
This study was aimed to determine the frequency of increase in intra-renal resistive index (RI) in patients with acute unilateral ureteric obstruction due to calculus.
Objective: To determine the diagnostic accuracy of renal arterial resistive index on doppler ultrasound in patients with acute renal colic to diagnose obstructive uropathy taking non-enhanced helical computed tomography as the gold standard.
Each participant underwent Doppler ultrasonography three times to measure the diameter of the vertebral artery, the peak systolic velocity (PSV), the resistive index (RI), and the vertebral artery flow volume; the mean of the three measurements was calculated for each patient, for the OSA and control groups, and for various subgroups.